{ config, lib, pkgs, utils, ... }:

let
  cfg = config.services.archivebox;
  jobUnitName = name: "archivebox-job-${utils.escapeSystemdPath name}";
  jobType = { name, options, ... }: {
    options = {
      urls = lib.mkOption {
        type = with lib.types; listOf str;
        description = "List of links to archive.";
        example = lib.literalExpression ''
          [
            "https://guix.gnu.org/feeds/blog.atom"
            "https://nixos.org/blog/announcements-rss.xml"
          ]
        '';
      };

      extraArgs = lib.mkOption {
        type = with lib.types; listOf str;
        description = ''
          Additional arguments for adding links (i.e., {command}`archivebox add
          $LINK`) from {option}`links`.
        '';
        default = [ ];
        example = lib.literalExpression ''
          [ "--depth" "1" ]
        '';
      };

      startAt = lib.mkOption {
        type = with lib.types; str;
        description = ''
          Indicates how frequent the scheduled archiving will occur. Should be
          a valid string format as described from {manpage}`systemd.time(5)`.
        '';
        default = "weekly";
        defaultText = "weekly";
        example = "*-*-01/2";
      };
    };
  };

  mkJobService = name: value:
    lib.nameValuePair
      (jobUnitName name)
      {
        description = "Archivebox download group '${name}'";
        after = [ "network.target" ];
        documentation = [ "https://docs.archivebox.io/" ];
        preStart = ''
                  mkdir -p ${lib.escapeShellArg cfg.archivePath}
        '';
        path = [ cfg.package ] ++ cfg.extraPackages;
        script = ''
          echo "${lib.concatStringsSep "\n" value.urls}" \
            | archivebox add ${lib.concatStringsSep " " value.extraArgs}
        '';
        serviceConfig = {
          User = "archivebox";
          Group = "archivebox";

          LockPersonality = true;
          NoNewPrivileges = true;

          CapabilityBoundingSet = [ ];
          AmbientCapabilities = [ ];

          PrivateTmp = true;
          PrivateDevices = true;

          ProtectControlGroups = true;
          ProtectClock = true;
          ProtectKernelLogs = true;
          ProtectKernelModules = true;
          ProtectKernelTunables = true;
          ProtectProc = "invisible";
          ProtectHome = true;
          ProtectSystem = "strict";

          RestrictAddressFamilies = [
            "AF_LOCAL"
            "AF_INET"
            "AF_INET6"
          ];
          RestrictNamespaces = true;

          SystemCallFilter = [ "@system-service" ];
          SystemCallErrorNumber = "EPERM";

          StateDirectory = "archivebox";
        };
      };

  mkTimerUnit = name: value:
    lib.nameValuePair (jobUnitName name) {
      description =
        "Archivebox download job '${name}'";
        after = [ "network.target" ];
        documentation = [ "https://docs.archivebox.io/" ];
        timerConfig = {
          Persistent = true;
          OnCalendar = value.startAt;
          RandomizedDelaySec = 120;
        };
        wantedBy = [ "timers.target" ];
    };
in
{
  options.services.archivebox = {
    enable = lib.mkEnableOption "Archivebox service";

    package = lib.mkPackageOption pkgs "archivebox" { };

    jobs = lib.mkOption {
      type = with lib.types; attrsOf (submodule jobType);
      description = "A map of archiving tasks for the service.";
      default = { };
      defaultText = lib.literalExpression "{}";
      example = {
        illustration = {
          urls = [
            "https://www.davidrevoy.com/"
            "https://www.youtube.com/c/ronillust"
          ];
          startAt = "weekly";
        };

        research = {
          urls = [
            "https://arxiv.org/rss/cs"
            "https://distill.pub/"
          ];
          extraArgs = [ "--depth 1" ];
          startAt = "daily";
        };
      };
    };

    extraPackages = lib.mkOption {
      type = with lib.types; listOf package;
      description = ''
        A list of additional packages to be set within the download jobs. By
        default, it sets the optional dependencies of ArchiveBox for additional
        download formats and capabilities.
      '';
      default = with pkgs; [
        chromium
        nodejs_latest
        wget
        curl
        yt-dlp
      ] ++ lib.optional config.programs.git.enable config.programs.git.package;
      example = lib.literalExpression ''
        with pkgs; [
          curl
          yt-dlp
        ]
      '';
    };

    webserver = {
      enable = lib.mkEnableOption "ArchiveBox web server";

      port = lib.mkOption {
        type = lib.types.port;
        description = "The port number to be used for the server at localhost.";
        default = 8000;
        example = 8888;
      };
    };
  };

  config = lib.mkIf cfg.enable (lib.mkMerge [
    {
      systemd.services = lib.mapAttrs' mkJobService cfg.jobs;
      systemd.timers = lib.mapAttrs' mkTimerUnit cfg.jobs;

      users.users.archivebox = {
        group = config.users.groups.archivebox.name;
        isNormalUser = true;
        home = "/var/lib/archivebox";
      };
    }

    (lib.mkIf cfg.webserver.enable {
      systemd.services.archivebox-server = {
        description = "Archivebox web server";
        after = [ "network.target" ];
        documentation = [ "https://docs.archivebox.io/" ];
        wantedBy = [ "graphical-session.target" ];
        serviceConfig = {
          User = "archivebox";
          Group = "archivebox";

          ExecStart = "${pkgs.archivebox}/bin/archivebox server localhost:${
            toString cfg.webserver.port
          }";

          CapabilityBoundingSet = [ "CAP_NET_BIND_SERVICE" ];

          Restart = "on-failure";
          LockPersonality = true;
          NoNewPrivileges = true;

          PrivateTmp = true;
          PrivateUsers = true;
          PrivateDevices = true;
          ProtectControlGroups = true;
          ProtectClock = true;
          ProtectKernelLogs = true;
          ProtectKernelModules = true;
          ProtectKernelTunables = true;

          RestrictAddressFamilies = [
            "AF_LOCAL"
            "AF_INET"
            "AF_INET6"
          ];
          RestrictNamespaces = true;

          SystemCallFilter = [ "@system-service" ];
          SystemCallErrorNumber = "EPERM";
          StateDirectory = "archivebox";
        };
      };
    })
  ]);
}